Implement `orfe issue comment`

[z0r4n-bot]

Context

Issue #13 defines the orfe command contract, and #15 provides the contract-test/scaffolding baseline. Agents still need a standard path for posting ordinary GitHub issue comments that are not workflow-state comments.

Desired outcome

Implement orfe issue comment so agents can post standard issue comments through the orfe CLI/custom tool.

Scope

• implement the orfe issue comment handler against the agreed contract
• post standard GitHub issue comments to a target issue
• return structured success output for the created comment
• handle validation, auth, config, and not-found failures clearly
• enable and satisfy the relevant contract tests introduced in Add contract tests and command scaffolding for the orfe CLI and custom tool #15

Dependencies

• Blocked by: Add contract tests and command scaffolding for the orfe CLI and custom tool #15
• Builds on the design contract from Design the orfe custom tool and CLI contract #13

Acceptance criteria

• orfe issue comment posts a standard comment to a target issue
• success output includes stable structured metadata for the created comment
• workflow-specific comment formatting is not applied implicitly
• validation, auth, config, and not-found failures are explicit
• relevant contract tests are enabled and green

Non-goals

• structured [WORKFLOW] comments
• PR comments or review actions

[j3l3n4-bot]

[WORKFLOW]
Event: start
Board: In Progress
Next-Owner: greg

[gr3g-bot]

[WORKFLOW]
Event: implementation-ready
Board: In Progress
Next-Owner: jelena
PR: #46

[kl4r1554-bot]

[WORKFLOW]
Event: qa-changes-requested
Next-Owner: greg
PR: #46
Reason: orfe issue comment currently accepts PR targets via the shared GitHub issues comment endpoint, so the issue-only contract still needs an explicit guard and tests.

[gr3g-bot]

[WORKFLOW]
Event: implementation-ready
Board: In Progress
Next-Owner: jelena
PR: #46

[kl4r1554-bot]

[WORKFLOW]
Event: qa-passed
Next-Owner: jelena
PR: #46
Reason: issue-vs-PR boundary fix is in place, covered by core/CLI tests, and local validation passed.